The buckle-type sheet folding apparatus has a plurality of buckles into which sheets to be folded are inserted by a length corresponding to a predetermined folding position. In each of the buckles, a stopper whose position is adjustable is arranged so that the sheet is stopped by colliding its leading end with the stopper so as to be set at the folding position. At an inlet of each of the buckles, a pair of driven intake rollers is arranged opposite to each other so as to take the sheet into the associated buckle and a pair of driven discharge rollers is arranged opposite to each other so as to fold a portion of the sheet deflected from the associated buckle outward.
Then the sheet is fed to the buckle-type sheet folding apparatus along a sheet feed path and nipped between the pair of driven intake rollers at the inlet of the first buckle and taken into the first buckle. When the leading end of the sheet collides with the stopper of the first buckle, the sheet deflects from the first buckle outward in the neighborhood of the inlet of the first buckle and the outward deflected portion of the sheet is nipped between the pair of the discharge rollers so as to be folded.
When the sheet is further folded, the folded sheet is inserted into the second buckle with its fold line in the lead by the pair of driven intake rollers at the inlet of the second buckle. When the leading end of the folded sheet collides with the stopper of the second buckle, the folded sheet deflects from the second buckle outward in the neighborhood of the inlet of the second buckle and the outward deflected portion of the sheet is nipped between the pair of discharge rollers of the second buckle so as to be further folded. The sheet is similarly folded predetermined number of times and finally the folded sheet is discharged from the sheet folding apparatus.
Thus, according to one buckle-type sheet folding apparatus, sheets are folded up in a direction perpendicular to a sheet feed direction according to a predetermined folding pattern (consisting of only at least one mountain fold, only at least one valley fold or a combination of mountain and valley folds) so that an accordion-folded sheets can be produced, and, in some cases, in order to further fold the accordion-folded sheets in a direction perpendicular to the folding lines, two buckle-type sheet folding apparatuses are perpendicularly connected to each other.
In such cases, the sheets increase their thickness and stiffness by being folded like an accordion by the first (upstream) buckle-type sheet folding apparatus and, if the accordion-folded sheets are directly fed from the first buckle-type sheet folding apparatus to the second (downstream) buckle-type sheet folding apparatus, the misalignment of folding lines and dull folding lines and so on are possibly caused. Therefore, in the prior art, the first sheet folding apparatus is provided with a scoring machine which forms a score or scores on the folded sheets outputted from the first buckle-type sheet folding apparatus according to a folding pattern achieved by the second buckle-type sheet folding apparatus.
An example of conventional scoring machines is disclosed in JP 2011-152982 A1. The scoring machine disclosed in JP 2011-152982 A1 comprises horizontal upper and lower rotary shafts, a plurality of first rollers mounted on the upper rotary shaft, and a plurality of second rollers mounted on the lower rotary shaft in a manner such that the second rollers are paired with the first rollers. Each of the first and second rollers is provided with a stop screw and fixed to the desired position by screwing the stop screw. The respective paired first and second rollers are arranged opposite to each other, and one of the respective paired first and second rollers is a convex roller having an annular projection at outer periphery thereof and the other of the respective paired first and second rollers is a concave roller having an annular groove at outer periphery thereof.
A guide rod is attached to a frame at its both ends and extends parallel to the upper rotary shaft above the upper rotary shaft and a guide rod is attached to the frame at its both ends and extends parallel to the lower rotary shaft below the lower rotary shaft. A slider is slidably attached to a pair of the guide rods. In addition, a stepping motor and an encoder are arranged in the neighborhood of the both ends of the guide rods, and a timing belt extends between rotary shafts of the stepping motor and encoder through pulleys. The slider is fixed to the timing belt and slides with the circulation of the timing belt.
A sensor for detection of the annular projections of the concave rollers as swell as a positioning gauge for positioning of the annular projections of the concave rollers are fixed to each of the upper and lower portions of the slider. In this case, the upper sensor and positioning gauge are provided exclusively for the convex rollers of the upper rotary shaft and the lower sensor and positioning gauge are provided exclusively for the convex rollers of the lower rotary shaft.
Thus the information of a folding pattern achieved by the second folding apparatus is inputted by an operator to a control unit of the scoring machine and a combination of the first and second rollers as well as an array of each pair of the first and second rollers on the upper and lower rotary shafts corresponding to the folding pattern is displayed on a display of the control unit. Then the operator mounts the first and second rollers on the upper and lower rotary shafts according to the array displayed on the display and attaches the upper and lower rotary shafts to the frame of the scoring machine.
Next, the slider slides along the pair of the guide rods while the upper and lower sensors detect the current positions of the annular projections of the convex rollers of the upper and lower rotary shafts. Then the slider (gauges) slides to the specified position of each convex roller according to the order of selection of the convex rollers based on the information of both the current positions and the specified positions of the convex rollers. Whenever the slider (gauge) stops at the specified position of the convex roller, the associated convex roller is positioned and fixed by hand in such a manner that the position of the annular projection thereof corresponds to the gauge, and then the associated concave roller is positioned and fixed in such a manner that the annular groove thereof engages with the annular projection of the convex roller.
Thereafter a sheet to be fed to the buckle-type sheet folding apparatus is inserted between the pairs of first and second rollers and the first and second rollers are rotated by hand so as to form a score or scores on the sheet, and thereby it is checked whether the score or scores formed on the sheet agree with the folding pattern or not, and the position setting of the first and second rollers are preformed again depending on the result of the checking.
By the way, in normal folding patterns, the convex rollers are necessarily mounted on both the upper and lower shafts so that the scoring machine needs the sensor and gauge for the convex rollers of the upper rotary shaft and the sensor and gauge for the convex rollers of the lower rotary shaft. Consequently, the scoring machine has a defect that its size becomes bigger and its structure is complicated. Therefore, in the prior art, it was necessary to arrange the structure for positioning the upper and lower rollers of the scoring machine (the slider and the mechanism for guide and drive of the slider) outside the buckle-type sheet folding apparatus as a unit separate to the buckle-type sheet folding apparatus.